USB, universal serial bus, is a common electronic connector interface applied to electronic devices. In order to be smaller and portable, a micro USB electrical connector is developed, which is usually equipped with a connection hole and a corresponding transmission line for various portable electronic apparatuses such as a smart mobile communications device and a digital camera.
Conventionally, a Micro USB electronic connector includes an insulation housing and a tongue plate structure formed at the front portion of the insulation housing, a plurality of terminals is configured on the insulation housing and the tongue plate structure, and a hollow shell encloses the insulation housing and the tongue plate structure. In order to prevent moisture entering from one side of the hollow shell into another side of the hollow shell, a sealing material, such as a waterproof adhesive bulk with large area, is applied to cover the rear portion of the insulation housing, so that the sealing material is filled into the gaps between the hollow shell, the insulation housing and the plurality of terminals, to ensure the electronic connector is waterproof.
However, the cost of the conventional sealing material is high; additionally, the sealing material is commonly available in a liquid form, for forming the waterproof adhesive bulk in larger areas, so the sealing material requires a drying procedure for a longer time, resulting into additional costs for the manufacturer. Consequently, there is an urgent need for the manufacturers of the electronic connector to solve the drawbacks raised by the conventional.